SF 





WEIGHTS AND MEASURES 



Regulations Relating to Cream Test Scales and Bab- 
cock Milk and Cream Test Bottles 



Prescribed by 

J. Q. EMERY, 

Ex Officio State vSuperintendent of Weights and Measures 

of 
WISCONSIN 



ISSUED MARCH 3, 1914 



6F '2-53 



0, OF S, 



-X 



STATE OF WISCONSIN 

OFFICE OF 

DAIKY AND FOOD COMMISSION AND WEIGHTS AND 

MEASURES. 

IMadison, January 17, 1914. 

To Wisconsin Sealers of Weights and Measures : 

Subsection 6 of section 1659 of the Wisconsin statutes eon- 
tains the following provision : 

"The superintendent of weights and measurers sliall 
issue from time to time, regulations for the guidance of all 
sealers, and the said regulations shall govern the procedure 
to l)e folloAved by the aforesaid officers in the discharge 
of their duties. In said regulations he shall prescribe the 
amount of tolerance to be allowed." 

In obedience to the requirements of this statute, the following 
regulations are prescribed for the guidance of sealers of weights 
and measures in the performance of their official duties so far 
as the same relate to the subject of Babcock milk test bottles, 
standard Babcock pipettes, Babcock cream test bottles, and 
cream test and butter fat test scales. 

Babcock ]\Iilk Test Bottles. 

Babcock milk test bottles complying with the following spe- 
cifications shall be sealed : 

The standard Babcock test bottles for milk shall have a 
capacity of two cubic centimeters for each 10 per cent marked 
on the necks thereof. 

The necks of the standard Babcock milk test bottles shall be 
graduated from zero to 10 per cent and the graduated scale 
shall be 75 millimeters in length, with an allowable tolerance of 
5 millimeters either above or below. The graduated scale shall 
be divided into per cent and fifth per cent divisions. The 
tifth per cent graduation marks shall be not less than 3 milli- 



— 4 — 





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meters in Icii^'th and the per cent ijraduation marks sliall 
be not less than !](> millimeters longer than the fifth per cent 
graduations. Each per cent graduation shall be numbered and 
the tolerance for the entire graduated scale or for any part 
thereof ssluill not exceed one-tenth of one i)er cent. 

The necks shall be cylindi'ical for at least T) milliiuctei-s below 
the lowest and above the highest gi-aduation nuirk. The top of 
the necks shall be tiared to an interior diameter of not less than 
10 millimeters. 

The capacity of the bulb up to the junction of the neck shall 
be not less than 40 cubic centimeters. 

The total height of the bottle shall be between 150 and 165 
millimeters. 

Kach bottle shall bear either a grountl surface for identifi- 
cation numl)er or a permanent identification number. 

Subsection 1 of section 1404aa of the Wisconsin statutes pro- 
vides as follows : 

"In the use of -the Babcock test, the standard milk 
measures or pipettes shall have a capacity of seventeen 
and six tenths cubic centimeters, and the standard test tubes 
or bottles for milk shall have a capacity of two cubic cen- 
timeters for each ten per cent marked on the necks thereof ; 
cream shall be tested by weight and the standard unit for 
testing shall be eighteen grams, and it is hereby made a 
misdemeanor to use any other standards of milk or cream 
measure where milk or cream is purchased by or furnished 
to creameries or cheese factories and where the value of 
said milk or cream is determined by the per cent of butter 
fat contained in the same, or wherever the value of milk or 
cream is determined by the per cent of butter fat con- 
tained in the same by the Babcock test." 

Referring to the foregoing provisions of law and other laws 
prescribing the duties of the state superintendent of weights and 
measures, Attorney Genei-al Owen has rendered tlie following 
ofificial opinion : 

"The fact that the statute says that the standard test 
tubes or bottles shall have a capacity of two cubic centi- 
Jneters for each 10 per cent marked on the necks thereof 
implies that the necks should have marked thereon the 10 
per cent mark. I believe that a so-called milk test bottle 
having only 3 per cent mark on the neck is, therefore, 
not in compliance with the provision of this law^ and you 
are, therefore, instructed that yoii would not be warranted 
in approving the same." 



_6 — 



Standard Babcock Pipettes. 

The standard pipettes shall have a capacity of 17.6 cubic centi- 
meters. 

The total length of pipette shall be not more than 330 milli- 
meters (131/4 inches). 

The outside diameter of suction tube shall be 6 to 8 milli- 
meters. The length of the suction tube shall be 130 milli- 
meters. The outside diameter of the delivery tube shall be 4.5 
to 5.5 millimeters. The length of the delivery tube shall be 
100 to 120 millimeters. The distance of the graduation mark 
above the bulb shall be 30 to 60 millimeters. The nozzle shall 
be straight. When filled with water at 20° C. delivery shall 
be in 5 to 8 seconds. The tolerance shall not exceed .05 cubic 
centimeter. 

A pipette having a capacity of 18 cubic centimeters or hav- 
ing any other capacity than* that above specified, namely 17.6 
cubic centimeters which is the only pipette that complies with 
the terms, of the law, must not be sealed. 

Note. Section 1494aa of the "Wisconsin statutes contains the 
following provision : 

' ' Cream shall be tested by weight and the standard unit 
for testing sha;ll be eighteen grams, and it is hereby made 
a misdemeanor to use any other standards of * * * 
cream measure where * * * cream is purchased by or 
furnished to creameries or cheese factories and where the 
value of said * * * cream is determined by the per 
cent of butter fat contained in the same, or wherever the 
value of * * * cream is determined by the percent of 
butter fat contained in the same by the Babcock test," 

Babcock Cream Test Bottles. 

Babcock cream test bottles of the following types and com- 
plying with the following specifications are to be sealed: 

Type A. Thirty per cent, 18 gram, 6 inch, i/o per cent grad- 
uations. Each 5 per cent on the neck of the bottle shall rep- 
resent a volume of 1 cubic centimeter. 

The neck of the bottle shall be graduated from zero to 30 
per cent and the graduated scale shall be 75 millimeters^ 
in length, with an allowable tolerance of 8 millimeters 
above or below\ The graduated scale shall be divided into 5 



— 7 — 

per cent, 1 per cent and Yi per cent divisions. The Vii P^'i" ^^^^^ 
graduation marks shall be not less than 3 millimeters in length. 
The 1 per cent graduation marks shall be not less than IVij 
millimeters longer than the Vo per cent graduations. The 5 
per cent graduation marks shall be not less than IVl. millimeters 
longer than the 1 per cent graduation marks. Each 5 per cent 
graduation shall be numbered. The allowable tolerance for 
calibration shall not exceed i/o per cent for the entire graduated 
scale or for any part thereof. 

The capacity of the bulb up to the junction of the neck shall 
be not less than 40 cubic centimeters. 

Each bottle shall bear either a ground glass surface for iden- 
tification number or a permanent identification number. 

The neck shall be cylindrical for at least 5 millimeters below 
the lowest and above the highest graduation mark. The top 
of the neck shall be flared to an interior diameter of not less 
than 10 millimeters. 

The standard unit for- testing shall be 18 gi-ams. 

The total height of the bottle shall be between 150 and 165 
millimeters (5% and GVli inches). 

Tyi)c B. Thirty per cent, 18 gram, 9 inch, .2 per cent grad- 
uations. 

The neck of the bottle shall be graduated from zero to 30 per 
cent and the graduated scale shall be 125 millimeters in length, 
with an allowable tolerance of 10 millimeters either above or 
below. The graduated scale shall be divided into 5 per cent, 
1 per cent and .2 per cent divisions. The .2 per cent grad- 
uation marks shall be not less than 3 millimeters in length. 
The 1 per cent and 5 per cent graduation marks shall be not 
less than 1.5 millimeters longer than the .2 per cent graduations. 
The allowable tolerance for calibration shall not exceed .2 
per cent for the entire graduated scale or for any part thereof. 

The total height of the bottle shall be between 210 and 225 
millimeters (8i/4 and Syg inches). 

All other specifications are to be the same as for Type A. 

Type C. Forty per cent, 18 gram, 6 inch, 1/2 per cent grad- 
uations. 

The neck of the bottle shall be graduated from zero to 40 
per cent and the graduated scale shall be 75 millimeters in 
length, with an allowable tolerance of 8 millimeters either above 
or below. 



All other speeiticatioiis are to be the same as for Type A. 

Type D. Fifty per cent, 18 gram, 7 inch, i/o per cent grad- 
uations. 

The neck of the bottle shall be graduated from zero to 50 
per cent and the graduated scale shall be 105 millimeters in 
length, with an allowable tolerance of 10 millimeters either above 
or below. 

The total height of the bottle shall be l)etween 180 and 195 
millimeters (Ti/y and 7-)4 inches). 

All other specifications are to ))e the same as for Type A. 

Type E. Fifty per cent, 18 gram, 9 inch, i/^ per cent grad- 
uations. 

The neck of the bottle shall he graduated from zero to 50 per 
cent and the graduated scale shall be 125 millimeters in length, 
with an allowable tolerance of I'D millimeters either above or 
below. 

The total height of the l)ottle shall be between 210 and 225 
millimeters (8V4 and Syg inches). 

All other specifications are to l)e the same as for Type A. 

Referring to the provisions of section 1491aa of the "Wisconsin 
statutes hereinbefore quoted, Attorney General Owen has render- 
ed the following official opinion relative to 9 gram cream test 
bottles : 

"Under this statute it is provided that 'cream shall be 
■tested by weight and the standard unit for testing shall 
be 18-grams and it is hereliy made a misdemeanor to use 
any other standards of milk or cream measure,' etc. As 
18 grams are expressly mentioned as the standard unit 
used in testing, and as no mention is made of a 9-gram 
standard unit, I am of the opinion that only the 18-gram 
cream test bottles can be used and the 9-gram cream test 
bottles should be condemned." 

Cream Test and Butter Fat Test Scales. 

The scale shall lie provided with a graduated plate of at 
least ten divisions over wliich the pointer plays. 

The pointer shall reach to the graduated divisions and shall 
terminate in a fine point to enable the readings to be made 
clearly and distinctly. 

The clear interval between the divisions on the graduated 
face shall not 1)e less than .05 inch. 



. — 9 — 

Beam scales and trip l)alances provided with knife edges and 
bearings shall l>e provided with leveling screv>^s and an attached 
level. 

The scale shall be so constructed and adjusted that when the 
pans are released or disturbed the pointer will return to rest 
at the zero mark. 

The addition of 32.4 milligrams or one half grain to tlie scale 
when loaded to capacity shall cause a movement of the pointer 
at least equal to one division on the graduated face. 

The tolerance either in excess or deficiency when the scale 
is fully loaded shall be one grain. 

Weights. A tolerance of 20 milligrams is allowable in 18 
gram weights and 10 milligi'ams in 9 gram weights. Tlie man- 
ufacturers' tolerance shall be one half this amount. 

Note. To avoid lia])ility of penalty for violation of the 
weights and measures law by the use of any unsealed weight, 
scale, measure or measuring appliance of any description, in- 
cluding new appliances, or any such appliance that has not 
been sealed within one year, owners of the same should give 
notice in writing to >the state superintendent of weights and 
measures, Madison, Wis., or to the city sealer if in a city hav- 
ing a city sealer of weights and measures, of the fact that they 
have such weight or measure or weighing or measuring device, 
giving a description of the same and its location. See subsection 
3, section 4432 "Wisconsin statutes. 





Da%r\j cDtd Food Coniniissioner, 
Ex officio State Superintendent of Weights (Did Measures. 



10 



Office op 
Dairy and Food Commission and Weights and Measures. 

Madison, Wis., March 4, 1914. 

To Cheese Factory and Creamery Managers, Cheese Makers 
and Butter Makers :, 

Paragraph 3 of section 1659 of the Wisconsin statutes re- 
lating to weights and measures places a general supervision of 
all weights and measures and weighing or measuring devices 
of the state in the hands of the state superintendent of weights 
and measures. It further provides that he or his inspectors by 
his direction shall, upon the written, request of any citizen, 
firm or corporation, or educational institution of the state, test 
or calibrate weights, measures, weighing or measuring devices, 
and instruments or apparatus used as s'tandards in this state. 

Under the provisions of this act, owners of creameries and 
cheese factories may send to the office of weights and measures 
at Madison, Wis. any Babcock milk, cream, or butter test 
bottles, any milk pipettes, and any scales or weights used in 
tile weighing of cream samples, and the same will be tested. 
No fees are charged for testing. Many managers are no^y or- 
dering their new supplies sent direct to the office of weights 
and measures for testing and sealing, thus insuring accuracy 
before being put to use, with little or no inconvenience. In 
sending in old glassware, it is best to send only part of the supply 
on hand at one time, as sometimes several weeks may elapse 
before the glassware can be returned. 

In sending apparatus for testing and sealing the following 
rules should be complied with: 

1. Address all packages to J. Q. Emery, Office of Weights 

and INIeasures, State Capitol, Madison, Wis. 

2. The name and address of consignor should be placed on 

the outside of the package. 

3. Transportation charges on packages should be prepaid. 



— 11 — 

4. If consignor desires package to be returned by parcel 

post, postage should be enclosed in letter to pay for 
return of same. 

5. Bottles to be tested must be thoroughly cleaned before 

sending, so that all sediment or deposit on the inside 
of the bottles is removed. No tests will be made of 
glassware that is not thoroughly cleaned when sub- 
mitted. 

6. Extreme care should be exercised in packing such glass- 

ware or scales for shipment, as this department will 
not be responsible for breakage. 

J. Q. EMERY, 

Dairy and Food Commissio7ier, 
Ex officio State Superintendent of Weigh ts and Measures. 



12 — 



CREAM TEST SCALES AND BABCOCK TEST l^OTTLES. 
By F. P. DowNiiVG, Chief Inspector of Weights and Measures. 

Cream Test Scales. 

Many articles have been published upon the testing of milk 
and cream by what is commonly known as the Babcoek method. 
In obtaining the percent of milk fat by this means the operator 
starts with a known volume or weight of the sample, places it 
in a graduated milk or cream bottle, treats it Avith sulphuric 
acid and then after eentrifuging or whirling the bottle a defi- 
nite period, reads the percent of fat directly from the bottle. 
In making the above test, skill and experience are required to 
secure accurate results. But no matter how careful the op- 
erator may be, it will be imposilbe for him to get correct results 
if he is not provided with accurate glassware and sensitive 
and accurate scales. 

In the past, the creameries of the state have been obliged to 
depend largely upon the advice of salesmen when ordering 
supplies and apparatus with which to work. This has resulted 
in the purchase of certain types of scales entirely untit for the 
purpose for which they w^re purchased, and the use of such 
scales has been the cause of great errors and heavy losses. 

There was a time when an 18 cc. cream pipette was considered 
sufficiently accurate to use in making cream determinations. 
But when it became known that such a pipette would deliver 
17.9 grams of a 10% cream and only 15.8 grams of a 50% cream, 
the cream pipette was replaced by various types of cream test 
scales. The wide range in the specific gravity of cream showed 
the unreliability of the use of a pipette. Every intelligent 
creameryman is now aware of this. But it is not so generally 
known that errors approximately as great as those obtained 
through the use of the cream pipette may be obtained by the use 
of inaccurate and insensitive cream test scales. 

The better class of books on the testing of cream give minute 
explanations to the operator concerning various ways in which 



— 13 — 

mistakes or errors in the reading of the fat content of the 
cream are produced, the proper temperature at which to take 
readings, the proper method of reading the meniscus, the 
strength of the acid to be used, and the number of revolutions 
made by the centrifuge. These and other essential details are 
described, but little or nothing has ever been published with 
regard to the errors that arise through the use of inaccurate 
cream test scales. 

Investigation shows that many of the mistakes now made in 
the creameries in this state in the determining of the fat con- 
tent of cream are due, not simply to the causes enumerated in 
the paragraph abo\e, but to the use of scales of improper con- 
struction. Frequently creamerymen find themselves unable to 
obtain duplicate tests in the determination of the percent of 
cream. Frequently farmers send their cream to the state dairy 
and food commission, to the university, or to the county train- 
ing schools for analysis and the results obtained differ from the 
readings given at the factory. In a number of instances, this 
difference has been found to be due to the use of cream scales 
that are not sufficiently sensitive. 

For the purpose of determining what types of cream scales 
were the most accurate and the best adapted to weighing a 
nine or eighteen gram sample of cream, state inspectors 
of weights and measures were sent to various creameries of the 
state to inspect the scales in use and to check up the weights 
obtained upon such scales by the creamerymen. The butter- 
maker at the creamery was asked to weigh a given number of 
samples of cream on liis scale, following the methods pursued 
by him in his daily work at the factory. In practically every 
instance, greater than usual care was taken in making the weigh- 
ings. The bottles containing the samples of cream were then 
securely corked and brought to the office of the state depart- 
ment of weights and measures at Madison, where they w^ere re- 
weighed on a delicate Becker office balance sensitive to .1 
milligram. The results obtained were indeed surprising and 
are given in Table I. 



— 14 



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— 15 — 

A careful study of this table reveals the fact that the more 
sensitive the scale the smaller the error resulting in weighing 
the cream. For instance, in test No. 1 the error of variation in 
duplicate tests amounted to 3.5%. In test No. 18 the variation 
was only .31%. The first scale had a sensitiveness of nine grains, 
whereas the latter was sensitive to one-third grain. In test No, 
3 made at Brodhead 9 gram samples wti'e weiglied and the varia- 
tion was 9.64%. It is clear from this that the smaller the 
charge the greater will be the percentage of error accruing 
through the use of a sluggish scale. If a nine gram sample had 
been taken in test No. 1 instead of an 18 gram, the variation in 
duplicate tests would undoubtedly have been about 7%. 

Tests Nos. 8 and 9 made at Ilelenville by Messrs. Moyes and 
H. L. Bornheimer show the personal factor in the use of a scale. 
In this instance Mr. Moyes, the buttermaker, weighed six samples 
of cream upon the scale, following which Mr. Bornheimer 
weighed the remaining six samples. On checking up the w^eights 
obtained by these two men, it was found that the variation in 
weighings in the case of Mr. Moyes amounted to 2.68%, while 
in the case of Mr. Bornheimer the variation was but 1.15%. 
The types of scales used in making the tests given in Table I 
were the twelve bottle torsion balance No. 3005, the twelve 
bottle Troemner balance No. 612, the four bottle Fairbanks 
Troemner balance No. 6612 with hanging pans, the four bottle 
torsion balance^ No. 1530, the two bottle torsion balance No. 
1515 and the one bottle torsion balance No. 1500. (See Illustra- 
tion). 

The figures show that accurate results are unobtainable 
through the use of the twelve bottle torsion balance 3005, the 
twelve bottle Troemner balance No. 612, and the four bottle 
Fairbanks balance No. 949 when the same are sluggish and in- 
sensitive in their action. 

Scale manufacturers concede that it is almost an impossibility 
to make a twelve bottle scale with overhead pans Avhich will 
remain sensitive to % grain and not show a greater error at full 
load than one grain. 

The figures in Table I likewise show that the specifications 
for cream scales must differ radically from the specifications 
applied to the ordinary commercial weighing appliances used 
in grocery stores and meat markets. It is not necessary for a 
grocer 's balance to be sensitive to one or two grains. He weighs 
his groceries in large quantities. An error of one grain in the 



— 16 — 




— 17 — 

weighing of a pound of tea Avoiild be an error of only 1 /TOGO of 
the load while an error of one grain in the Aveighing of a nine 
gram sample of cream would be an error of 1/139 of the sample, 
the proportionate error l)oing fifty times as great in the weight 
of the cream as it is in the weight of the tea. 

To show the losses resulting through the use of inaccurate 
scales, a few cases are cited, taking the figures from Table I. 

In the case of H. Ml. Zanders of Cross Plains, the average 
weight of the tests was 17.48 grams, the error being minus .52 
gi-ams or 2.89i%. The error on 10,000 lbs. of butter fat would 
amount to 289 lbs. At 25 cts. a pound for butter fat the loss 
to the patrons would be $|72.25. 

In the case of test No. 7, John Roberts of Fort Atkinson, the 
average weight of the tests was 18.31 grams, the excess weight 
being .31 grams or 1.72%. The error on 10,000 pounds would 
be 172 pounds. At 25 cts. a pound the loss to the creamery 
would be $43. 

In test No. 3 at the Bredhead Creamery the highest reading of 
the nine gram sample olitained showed an error of .6359 grams 
or 7.06%. The loss to the creamery on 100 pounds of butter fat 
at 25 cts. a pound in this case would amount to $1.76. The 
lowest individual reading obtained at the Brodhead Creamery 
was .2319 grams short of 9 grams or 2.57%. The gain to the 
creamery on 100 pounds of butter fat at 25 cts. a pound in this 
case would amount to 2.57 pounds valued at 64 cts. By using 
scales sensitive to Y- grain or less, the errors are very slight, 
almost negligible. 

The results obtained in Table T applied to scales in actual use, 
some of which were a number of years old. 

To be absolutely sure that the unfitness of the types of scales 
mentioned in Table I is due largely to the inherent constru9- 
tion of the scale and not to the operator of the scale, nor to im- 
perfections brought about through use, manufacturers of cream 
test scales were requested by the state department of weights 
and measures to submit different types of new scales which they 
manufactured. The manufacturers were perfectly willing and 
glad to cooperate with the department in this matter and in each 
case a loan of the different types of scales manufactured was 
made to the department. 



— 18 — 






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— 19 — 

Table II gives the results of the weighings made upon these 
new scales. Twelve 18 gram samples of cream were very care- 
fully weighed upon each type of scale, extreme care being taken 
in placing the cream in the Babcock bottles not to add an excess. 
If a few drops of cream in excess were accidentally poured into 
the bottle, the same were removed so as to bring the scale back 
as near as possible to a perfect balance. The samples were then 
reweighed upon the Becker office balance and the variations in 
weight recorded. The results obtained again show that the more 
sensitive the scale, the more accurate the weighings recorded and 
the less the variation of duplicate samples. By studying the 
variation of the duplicate weights in grams, it will be observed 
that the greatest variations were obtained upon the twelve bottle 
Fairbanks cream test scale No. 950, the four bottle Fairbanks 
cream test scale No. 949 and the twelve bottle torsion balance 
No. 30'05. In these experiments the twelve bottle Troemner 
balance with hanging pans. No. 6612, is the only type of twelve 
bottle cream test scale that gave reasonably accurate results. 

The errors resulting through the use of the twelve bottle 
Troemner No. 612 and the Troemner scale No. 60 are almost 
identical. It will be noted that the twelve bottle Troemner No. 
612 submitted to the state department of weights and measures is 
an exceptionally sensitive scale for one of this type. 

It seems necessary at this point to explain the meaning of the 
term sensitiveness. JMore technically speaking, this term should 
be called the "sensibility reciprocal". It -is defined as the 
weight in grains required to move the pointer over one scale di- 
vision. Where the scale was not provided with an indicator as 
was the case in the twelve bottle Troemner No. 612 the sensi- 
bility reciprocal was considered as the weight which when placed 
on the pan would move the pointer a distance equal to the thick- 
ness of the pointer, or about three millimeters. 

Comparing the results obtained on the twelve bottle Troemner 
No. 612 in Table II with the results obtained in Table I, it will 
be observed that the sensitiveness of this scale decreases rapidly 
with use. This is no doubt due to the fact that there are a large 
number of friction points. Exposure to moisture rusts the con- 
necting rods beneath the l)ase of the scale, producing sluggish- 
ness in its action. ' 

. Attention is called to the figures in the last row of Table II 
in which the error duo to a plus or minus reading of the pointer 



— 20 



one scale division is recorded. Tliese figures are obtained by 
multiplying the sensitiveness of the scale in milligrams by two. 
In the ordinary operation of cream test scales the operator un- 
doubtedly frequently overloads or underloads his scale an 
amount which would cause the pointer to deviate one division to 
the right or left. In doing this the error for the different types 
of scales depends strictlj^ upon the sensitiveness of the scale. 
By comparing the figures in this row wdth the figures shown in 
the row indicating the actual variation in grams of the dupli- 
cate weighings an idea is given of what proportion of the vari- 
ation is due to the use of a sluggish scale and what proportion 
is due to the personal element. 

There seems to be a prevailing opinion among creamerymen 
of the state that the use of a twelve bottle cream test scale re- 
sults in the saving of much time. To determine just what this 
saving would amount to a record was kept of the number of 
minutes required to make twelve weighings and the figures are 
recorded in the third line of Table 31. The results show that 
the more sluggish and insensitive the scale the less time is re- 
quired in making twelve weighings. It will be observed that 
twenty minutes were required to make twelve weighings on the 
twelve bottle Torsion balance No. 3005 and but twenty-three 
minutes in weighing twelve bottles upon the four bottle torsion 
balance No, 1530. This time included the balancing of the four 
bottle balance three times. Wliile the ability to make rapid 
weighings on a cream test scale is important, nevertheless accur- 
acy should never be sacrificed for speed. While it required 
three minutes more to make twelve weighings on the four bottle 
torsion ])alance than it did upon the twelve bottle torsion bal- 
ance, the percent of variation in the twelve bottle balance was 
about ten times greater than that obtained in the use of the 
four bottle balance. 

A cream test scale should fulfill the following requirements : — 
It should be sensitive to one drop of cream, which is approx- 
imately thirty-two milligrams or one half grain. The maximum 
error permissible at full load or less should not be in excess of 
64.8 milligrams or one gi-ain. If of the beam or lever type, it 
should ])e provided with leveling screws and a level so that the 
errors due to weighing on a scale out of level can be avoided. 
If provided with a tare Aveight this weight should not be so 
heavy that it is difficult to bring the scale into balance through 



21 — 



a very slight movement of the tare weight. A tare weight which 
moves upou a threaded rod is much easier to manipulate than 
one that slides along a smooth rod. The weight of samples of 
cream should not vary on different parts of the pan, which is 
found to be the ease with some of the twelve bottle cream test 
scales. The scale should be provided with a pointer which plays 
over a graduated indicator. It is extremely difficult to use a 
scale with two blunt pointers, such as are found in the twelve 
bottle Troemner cream test scale, and obtain accurate residts. 
The seale should respond quickly so that time will not be lost in 
the operation of weighing. 

In order that accurate testing be done in creameries, the op- 
erator must be provided with proper utensils. It is of the high- 
est importance that the seale be accurate and sensitive. It must 
be remembered, however, that even if a new scale does weigh 
accurately it will soon become sluggish and inaccurate if it is 
not properly cared for. Comparatively few creameries give 
proper care and attention to the cream test scales in use. They 
are left exposed in a damp, room and become rusted. Dirt 
and dust accumulate on the bearings. The weighings are fre- 
quently made upon surfaces that are not level. A scale, to weigh 
accurately, must be kept clean and free from the moisture and 
dirt of the factory. The life of the scale could be greatly pro- 
longed if the operator went to the slight additional expense of 
purchasing a glass frame or co\ er in which to keep his scale 
;when not in use. A level shelf should be provided for the scale. 
This shelf should be free from all jars and vibrations due to the 
movement of the machinery in the creamery. One of the state 
inspectors reports that in visiting a creamery he found that the 
operator had placed his cream test scale upon the top of the 
centrifuge while the same was in motion and was making his 
weighings under these totally unfit conditions. It it any wonder 
that inaccurate results are obtained under such adverse condi- 
tions ? 

Babcock Test Bottles. 

The Babcock method of testing milk and cream is volumetric, 
the unit of graduation being the true cubic centimeter or the 
volume occupied by 6ne gram of distilled water at 40° C. In 
the 18 gram bottle each cubic .centimeter represents 5% on the 
graduated neck of the bottle. 



— 22 — 

That there is great need in Wisconsin for establishing speci- 
fications relating both to the form' and accuracy of Babcock 
glassware is revealed by investigations carried on by the state 
department of weights and measures. Thousands of Babcock 
bottles have during the past year been tested by this depart- 
ment and large numbers liave been found inaccurately gradu- 
ated, in a few cases the inaccuracies amounting to as much as 
4% or 5% on a 50% cream test bottle. A bewildering variety 
of types of Babcock bottles is now listed in the catalogues of 
glass ware manufacturers. A few of this multitudinous variety 
of types of bottles are so constructed that they can be readily 
used in obtaining accurate results in the reading of the fat 
content of milk or cream. The remaining types are worse than 
worthless as they are misleading to the dairymen. The use of 
the wide neck bottle is especially objectionable. The use of 
bottles in which the graduations are placed very close together 
is likewise objectionable, it being impossible to obtain accurate 
results when either of the above objectionable types of bottles 
is used. 

In the reading of cream the fat content should be read to at 
least within .5%. This being the case, cream test bottles grad- 
uated in 1% divisions should not be sealed. Dividers should be 
used in making the reading. 

Specifications prescribing the minimum and maximum length 
of the graduated neck of both milk and cream bottles are neces- 
sary for two reasons. First, it is to the manufacturer's advan- 
tage to use tubing having a wide variation in diameter. If no 
limit is placed on the diameter of the tubing used, the manu- 
facturer to avoid waste uses up all available tubing, thus pro- 
ducing a varying percentage of bottles with extremely wide 
necks and graduations croAvded closely together. AVhile such 
bottles may be accurately calibrated they are difficult to read. 
Second, the graduations on the 6 inch cream test bottles, which 
originally did not exceed 30% or 40%), have been increased to 
50% or 55%. The graduations are thus crowded together so 
closely that accurate reading is practically impossible. It is 
not in the interest of accuracy to have the distance between 
graduations appreciably less than one millimeter. 

In determining types of bottles which will be approved for 
sealing by sealers of weights and measures, the work w^as done 
on the theory that specifications should be of such a nature as 



23 




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— 24 — 

to lead tO' the securing of accurate results. The work was not 
done on the theory that specifications for Babcock bottles should 
be such as to grant the manufacturer a wide latitude in the 
selection of his tubing. Neither are the specifications prepared 
on the theory that cream bottles should be so closely graduated 
as to permit the reading of cream with a high fat content when 
centrifuges of a narrow diameter are used. Accuracy must not 
be sacrificed for mere convenience; neither should the matter 
of a few dollars extra expense to the creamerymen be the essen- 
tial consideration. The purchase of defective glassware at any 
price is a short sighted policy. Such glass ware must utterly 
fail to accomplish the legitimate purpose of its use. 

Specifications are prescribed for five types of cream test 
bottles. When cream does not run above 30%, the 18 gram, 6 
inch, 30% cream test bottle with Yo'/o graduations can be used. 
It is not necessary in such cases to use the 40% or 50% bottle. 
If readings witliin .2% are desired, as is the case in research 
work or in cases for court, the 30%, 18 gram, 9 inch cream test 
bottle graduated in .2% divisions can be used. 

In most of the Wisconsin creameries the 40%, 18 gram, 6 
inch cream test bottle will l^e found to he graduated sufficiently 
high to test all samples of cream brought to the factory. In 
creameries where the percent of fat in the cream runs above 
40%, either the 50%, 18 gram, 7 inch cream test bottle or the 
50%, 18 gram, 9 inch cream test bottle can be used. Owing to 
the claim by dairymen that a large amount of breakage results 
through the use of the 9 inch bottle, a new type of bottle is 
approved, namely, the 50%, 18 gram, 7 inch cream test bottle 
adapted to use in centrifuges of wide diameter. 

Where creameries do not desire to go to the exi^ense of in- 
stalling a centrifuge that will hold 7 or 9 inch bottles, a 40%, 
18 gram, 6 inch bottle can be used. If cream, runs over 40%, a 
9 gram charge can be weighed into the bottle and 9 grams of 
water added before the ' acid is placed in the bottle. The read- 
ing obtained will have to be' nuiltiplied by two. When sensi- 
tive cream scales are used, the doubling of any error due to 
inaccurate M^eighings will be exceedingly slight. The dilution 
of concentrated cream with water causes it to approximate more 
closely the composition of milk, and it is to be borne in mind 
that the Babcock test was originally designed for the determi- 
nation of the butter fat of milk and not of cream. 



— 25 — 

Owing to the opinion of the attorney general that the law does 
not permit 87^ milk test hotth's graduated ti> .1'^ divisions 
being sealed, this type is not included in the spcridcations 
Furthermore, it is highly desirable from the stanili)oint of ac- 
curacy to have all milk bottles with necks of a])i)roximately the 
same diameter. In reading the fat content of milk, the reading 
is taken to the top of the meniscus. Shortening the diameter 
pf the neck changes the shape of this meniscus and produces an 
error in the reading which though small is a])pr('ciable. As 
many of the 8% bottles in use have narrower necks than the 
10% bottle; a constant error is thus introduced, if this type of 
bottle is used. 

The use of Babcock glassware complying with these specifica- 
tions will do away with many of the disputes between factory- 
man and patron now due to the use of inaccurate glassware. 



LIBKHKY Ul- LUNUKbbb 



000 895 829 4 



